Flatness Measurement Of Satellite-borne SAR Antenna And Adjustment Strategy For Position And Attitude

A certain satellite-borne SAR antenna is a kind of large aperture plane antenna,which is composed of several sub-antenna arrayed.When antenna is deployed in space,the error due to motors' motion and connection structures' assembling will make the antenna arrays are not in same plane.As a result,the electrical properties of the antenna will change worse,and the efficiency of SAR will also be influenced.This paper introduces flatness concept for describing the position deviation between sub-antennas.In order to improve the SAR antenna's flatness,this paper proposes a method for flatness measurement by doublehyphen line laser.In addition,this paper also researches on strategy for adjusting sub-antennas' position and attitude.Firstly,according to size parameters of antenna and its working conditions,this paper determine four kinds of the basic position relationship between sub-antenna.Establishing sub-antennas' fixed coordinate systems,this paper introduces Euler angles and homogeneous transformation matrix,and then derives homogeneous transformation relationship between sub-antennas' fixed coordinate systems.Secondly,this paper introduces the flatness measurement theory.Combining with actual measurement conditions,this paper determines the basic plane for measurement and the way for arranging sampling points of the measurement system.This paper describes the hardware and software of the measurement system,especially introducing its core hardware,double-hyphen line laser and signal receiving target.The introduction includes working principles and specific parameters of hardware.Thirdly,based on the conditions and equipment of lab,this paper builds simulation experiment system,and completes test experiment.The processing result of experiment data proves the feasibility of the measurement method.Researching on the error of the proposing measurement method,this paper analyses the sensitivity of the measurement method,and summarize the main factors which affect the accuracy of the method.Finally,considering that the light plane may be not parallel to the basic plane for measurement,this paper uses those known results of antenna flatness measurement to derive specific parameters for adjusting the attitude and position of sub-antennas.Referencing to the theory of robot arms' trajectory planning,this paper designs the motion of motors between sub-antennas.